new oil pump when you can, for now heavier oil. i agree with dan except that 20-50 is fine is you run the car at temp for long highway cruises and/or you live in a very hot area. lots of stop and go traffic where the engine is idling a lot, you are stuck in traffic and it's 90 to 100 degrees out, the 20w50 is fine.
cooler temps, short trips, engine rarely gets to max temp then 20w50 would be a bad idea.